1. Field of the Invention
The present invention relates to a machining simulation system including a numerical control apparatus configured to control a machining motion of a machine tool and a machining simulation apparatus configured to perform a simulation prior to an actual machining operation.
2. Description of the Related Art
A numerical control apparatus can control a machine tool according to numerical control information input by an operator of a production engineering division who can use a machining simulation apparatus. The machining simulation apparatus has a machining simulation function (including an interference check function) for checking an motion of a machine tool to be realized according to a machining command involved in the numerical control information. The machining simulation apparatus is, for example, constituted by a personal computer that can realize highly advanced performances according to software programs.
On the other hand, a numerical control apparatus of a worksite enables an operator to use a machining simulation function. For example, the machining simulation function provided by a numerical control apparatus includes checking beforehand an motion of a machine tool (including an interference check) to be used in a machining operation. Furthermore, the machining simulation function provided by the numerical control apparatus may include graphically displaying the progress of an actual machining operation if an operator cannot visually check the operation inside a machine tool after a door of the machine tool is closed.
After numerical control information has been determined by an operator of a production engineering division using the machining simulation apparatus, an operator of a worksite may modify the numerical control information according to machining processing environments. As a result, setup positions of a tool and a material according to the corrected numerical control information may differ from those determined by the operator of the production engineering division.
For example, a worksite environment may prevent preparation of a tool designated by an operator of the production engineering division, or may make it impossible to install the tool at a designated position. Accordingly, before performing actual machining work, an operator of the worksite uses the machining simulation function of the numerical control apparatus that can check an motion of the machine tool to be performed according to the numerical control information corrected according to the machining processing environment of the worksite.
FIG. 6 illustrates a conventional machining simulation apparatus 100 that can be used in a production engineering division. FIG. 7 illustrates a conventional numerical control apparatus provided on a worksite that can control a machine tool.
A numerical control information input unit 1 enables an operator to input numerical control information (e.g., machining simulation data and interference check data) via a keyboard 19. A numerical control information storage memory 2 stores the input numerical control information. A mechanical structure storage memory 3 stores various shape models including a tool rest, a main spindle, and a table of a machine tool, which are used for a machining simulation or an interference check.
A material shape setting/display unit 4 enables an operator to input a material shape model used in a machining simulation via the keyboard 19. A material shape storage memory 5 stores the input material shape model. The material shape setting/display unit 4 causes the display device 18 to display an operation screen that instructs an operator to input a material shape model and enables the user to confirm the input material shape model. FIG. 8 illustrates an exemplary operation screen displayed by the display device 18 according to the processing performed by the material shape setting/display unit 4.
A material setup position setting/display unit 6 enables an operator to input a material setup position via the keyboard 19. The material setup position indicates a position where the input material shape model is placed on a machine tool to be subjected to the machining simulation. A material setup position storage memory 7 stores the input material setup position. The material setup position setting/display unit 6 causes the display device 18 to display an operation screen that instructs an operator to input a material setup position and enables the user to confirm the input material setup position. FIG. 9 illustrates an exemplary operation screen displayed by the display device 18 according to the processing performed by the material setup position setting/display unit 6.
If a lathe grips and holds a material with a chuck attached to a main spindle, a relative distance between a reference point on a right-edge surface of the main spindle and a reference point of a material model can define the material setup position. If a machining center fixes and holds a material with a jig on a table, a relative distance between a predetermined reference point of the table and a reference point of a material model can define the material setup position.
A tool shape setting/display unit 8 enables an operator to input a tool shape model used in a machining simulation via the keyboard 19. A shape storage memory 9 stores the input tool shape model. The tool shape setting/display unit 8 causes the display device 18 to display an operation screen that instructs an operator to input a tool shape model and enables the user to confirm the input tool shape model. FIG. 10 illustrates an exemplary operation screen displayed by the display device 18 according to the processing performed by the tool shape setting/display unit 8.
Furthermore, a tool setup position setting/display unit 10 enables an operator to input a tool setup position via the keyboard 19. The tool setup position indicates a position at which the input tool shape model is placed on a machine tool to be subjected to the machining simulation. A tool setup position storage memory 11 stores the input tool setup position. The tool setup position setting/display unit 10 causes the display device 18 to display an operation screen that instructs an operator to input a tool setup position and enables the user to confirm the input tool setup position. FIG. 11 illustrates an exemplary operation screen displayed by the display device 18 according to the processing performed by the tool setup position setting/display unit 10.
If a lathe allows the attachment of a plurality of tools on a tool rest, the tool setup position may indicate the position of each tool on the tool rest or indicate a dimension relating to the installation, such as a relative distance between a reference point of the tool rest and a cutting edge point of a tool shape model. If a machining center has a main spindle to which a tool can be attached, the tool setup position may indicate a relative distance between a reference point on an edge surface of the main spindle and a cutting edge point of a tool shape model.
Similarly, a jig shape setting/display unit 12 enables an operator to input a jig shape model used in a machining simulation via the keyboard 19. A jig shape storage memory 13 stores the input jig shape model. The jig shape setting/display unit 12 causes the display device 18 to display an operation screen that instructs an operator to input a jig shape model and enables the user to confirm the input jig shape model. FIG. 12 illustrates an exemplary operation screen displayed by the display device 18 according to the processing performed by the jig shape setting/display unit 12.
If this system is applied to a lathe capable of gripping and holding a material with a chuck attached to a main spindle, the setup position of a chuck (i.e., jig) can be accurately determined. In such a case, the system may not include a unit configured to perform setting/display processing for a jig and a storage memory that can store setting data.
As described above, machining simulation data and interference check data (i.e., material shape model, tool shape model, setup position, and jig shape model) are stored in respective storage memories.
An motion simulation unit 14 reads the numerical control information from the numerical control information storage memory 2 and performs an motion simulation. The motion simulation includes reading a command relating to a machining operation involved in the numerical control information and generating a pseudo operation signal corresponding to a axis moving signal of a tool rest, a main spindle, or a table.
A graphic simulation unit 15 reads the material shape model from the material shape storage memory 5 and locates the retrieved material shape model on a desired position of the machine tool subjected to a graphic simulation according to the material setup position read from the material setup position storage memory 7. Then, the graphic simulation unit 15 reads the tool shape model from the tool shape storage memory 9 and locates the retrieved tool shape model on a desired position of the machine tool subjected to a graphic simulation according to the tool setup position read from the tool setup position storage memory 11.
Furthermore, the graphic simulation unit 15 reads the jig shape model from the jig storage memory 13 and locates the readout jig shape model on a predetermined position of the machine tool subjected to graphic simulation. Furthermore, the graphic simulation unit 15 performs a pseudo sequential motion of a tool rest, a main spindle, and a table that hold the tool shape model and the material shape model according to a pseudo operation signal received from the motion simulation unit 14. The display device 18 displays a state of this graphic simulation on its screen according to the processing of the graphic display unit 17.
An interference check unit 16 performs an interference check for determining whether the shift movement of a tool rest, a main spindle, or a table (i.e., simulation result by the graphic simulation unit 15) might interfere with a material, a tool, or a jig. Then, if the interference check unit 16 determines that any interference is possible, the display device 18 presents a graphic display (e.g., warning message) indicating the interference to an operator.
FIG. 7 illustrates an exemplary configuration of a numerical control apparatus 200. A numerical control information input unit 51 enables an operator to input numerical control information via a keyboard 72. A numerical control information storage memory 52 stores the input numerical control information.
The numerical control apparatus 200 comprises various units similar to the above-described units of the machining simulation apparatus 100. More specifically, a mechanical structure storage memory 57 is functionally similar to the mechanical structure storage memory 3. A material shape setting/display unit 58 is functionally similar to the material shape setting/display unit 4. A material shape storage memory 59 is functionally similar to the material shape storage memory 5. A material setup position setting/display unit 60 is functionally similar to the material setup position setting/display unit 6. A material setup position storage memory 61 is functionally similar to the material setup position storage memory 7. A tool shape setting/display unit 62 is functionally similar to the tool shape setting/display unit 8. A tool shape storage memory 63 is functionally similar to the tool shape storage memory 9. A tool setup position setting/display unit 64 is functionally similar to the tool setup position setting/display unit 10. A tool setup position storage memory 65 is functionally similar to the tool setup position storage memory 11. A jig shape setting/display unit 66 is functionally similar to the jig shape setting/display unit 12. A jig shape storage memory 67 is functionally similar to the jig shape storage memory 13.
In the example described, the system employs similar arrangements for setting/displaying/storing the material/tool shape models, the material/tool setup positions, and the jig shape model in order to simplify the description. In this respect, a numerical control apparatus and a machining simulation apparatus of a machining simulation system according to the present invention are not limited to similar existing units.
As described above, machining simulation data and interference check data (i.e., material shape model, tool shape model, setup position, and jig shape model) are stored in respective storage memories.
A numerical control information interpretation unit 53 reads the numerical control information from the numerical control information storage memory 52 and interprets the retrieved information. The numerical control information interpretation unit 53 transmits a axis movement command involved in the interpreted numerical control information to a axis movement command execution unit 54. Furthermore, the numerical control information interpretation unit 53 transmits other commands (e.g., a main spindle rotation command and a cutting fluid discharge command) to related execution units (not illustrated).
The axis movement command execution unit 54 generates a axis moving signal according to the axis movement command. In an actual work control, the axis movement command execution unit 54 transmits the generated axis moving signal to a servo control unit 55. The servo control unit 55 controls a servo motor 56 according to the axis moving signal. The servo motor 56 performs a axis moving operation for a tool rest, a main spindle, or a table of the machine tool.
If the numerical control apparatus 200 performs a machining simulation or an interference check concurrently with an actual work control, the axis movement command execution unit 54 transmits a axis moving signal to a graphic simulation unit 68. The graphic simulation unit 68 executes processing similar to that of the above-described graphic simulation unit 15 of the machining simulation apparatus 100. An interference check unit 69, a graphic display unit 70, and a display device 71 are functionally similar to those of the interference check unit 16, the graphic display unit 17, and the display device 18 of the machining simulation apparatus 100.
The interference check unit 69, if any interference is detected, transmits a stop signal to the servo control unit 55. The servo control unit 55 stops the axis movement of the tool rest, the main spindle, or the table.
If the numerical control apparatus 200 performs only a machining simulation or an interference check without performing an actual work control, the axis movement command execution unit 54 transmits a axis moving signal only to the graphic simulation unit 68 (i.e., does not transmit a axis moving signal to the servo control unit 55). Therefore, the servo motor 56 does not perform a axis moving operation for an actual work.
As described above, according to a conventional system, the machining simulation apparatus 100 provided in a production engineering division performs a machining simulation including an interference check prior to an actual machining operation. On the other hand, the numerical control apparatus 200 provided on a worksite performs a machining simulation including an interference check based on numerical control information reflecting actual machining conditions and corrections made by an operator of a worksite.
In other words, the production engineering division and the worksite independently perform the machining simulations based on different conditions. Therefore, the machining simulation apparatus provided in the production engineering division and the numerical control apparatus provided on the worksite are unable to mutually readjust the differences in the machining simulation conditions.
If the numerical control apparatus provided on the worksite repeatedly performs a machining simulation reflecting the specificity of the worksite (e.g., corrections according to machining conditions), simulation contents of the machining simulation apparatus provided in the production engineering division gradually separate from simulation contents of the numerical control apparatus provided on the worksite. The above-described conventional system cannot readjust the separated simulation contents and simulation conditions.
According to the description of the system disclosed in Japanese Patent Laid-open Application No. 5-42446, an apparatus performing an interference check can cooperate with a numerical control apparatus. More specifically, the numerical control apparatus actually moves a movable member and detects a position where the movable member interferes with a workpiece. The numerical control apparatus transfers the obtained positional information to a CAD/CAM apparatus having an interference check function.
However, in the above-described conventional system, the numerical control apparatus performs only a machining processing control and is simply combined with the CAD/CAM apparatus having a simulation function. In other words, the above-described conventional system cannot perform an adjustment between the machining simulation apparatus performing a simulation prior to an actual machining operation and the numerical control apparatus performing a simulation reflecting worksite information.
As described above, each of the machining simulation apparatus and the numerical control apparatus performs a machining simulation or an interference check. In this case, as apparent from the foregoing description, an operator of the machining simulation apparatus and an operator of the numerical control apparatus are required to independently set a material shape model, a material setup position, a tool shape model, and a tool setup position.
Accordingly, the following problems arise:    *1: Even after a material shape model, a material setup position, a tool shape model, and a tool setup position have been set for the machining simulation apparatus, similar data setting is required for the numerical control apparatus.    *2: An operator of the worksite is required to input all of the data required for the numerical control apparatus, thereby increasing the likelihood of data entry or setting errors.    *3: An operator of the machining simulation apparatus side is required to generate a paper document or other medium that describes or indicates preparatory planning information including setting data contents, such as a material shape model, set by a machining simulation apparatus and send it to the operator of the numerical control apparatus side.    *4: Any data corrected by the numerical control apparatus side according to a machining processing environment cannot be easily transmitted to the machining simulation apparatus side. Such corrected data cannot be transmitted unless a paper document or other medium is used.    *5: The machining simulation apparatus side cannot collect the data actually used in a machining operation and cannot establish a reusable database including such correction data. As a result, an environment of the machining simulation apparatus cannot be improved so as to fit to the environment of the worksite.